Atmospheric air samples were collected at 9 monitoring stations (A1 to A9) less than 2 km from the Paks Nuclear Power Plant (Paks NPP) and a background station (B24). The monthly integrated CO2 and total carbon (CO2+hydrocarbons (CnHm)) samples were collected to determine the excess 14C activity at the vicinity of the NPP. The measurements providing the 14C/12C ratio of the monthly integrated samples were carried out on a MICADAS type AMS at HEKAL. Due to the relatively low 14CO2 emission of PWR type Paks reactors and the local Suess effect, there was negligible excess 14C activity at the investigated stations in the pure CO2 fraction during the investigated 2 years period (2015-2016). On the contrary, there was a detectable (although minor) excess at every station in the CnHm fraction. In case of CO2, the average Δ14C excess was 3.8‰ and the highest measured value was 91.2‰ at the A3 station in February 2015. In case of CnHm, the average excess was 31.1‰ and the highest measured value was 319.1‰ at the A4 station in February 2016. We applied PC-CREAM 08 modelling to investigate the observed excess 14C activity at the environmental sampling stations, which depends on the distance from the NPP and the meteorological conditions, such as wind direction and wind speed. Meteorology data was collected at the operating area of the Paks NPP in a meteorology tower. The direct C-14 emission through the 120 m high stacks was measured in the NPP by liquid scintillation counting. These emission data and our model calculations explain the excess activity in the CnHm fraction at the A4 station, which is located only 915 m far from the NPP's stacks in the prevailing wind direction. The excess activity at A3 station (the farthest unit) probably came from the nearby NPP wastewater discharge point. The recently observed average excess and highest excess data is similar to the published data in former studies (Molnár et al., 2007; Veres et al., 1995) on Paks NPP, the highest 14CO2 and 14CnHm excess are just a little higher than it was in the earlier studies, but in these former studies, the A3 station was not equipped with a radiocarbon monitoring unit and the level of radiocarbon emission was almost invisible from the wastewater discharge point.

中文翻译：

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匈牙利Paks核电厂周围的先进大气14C监测。

在距帕克斯核电站（Paks NPP）和背景站（B24）不到2公里的9个监测站（A1至A9）收集了大气样品。每月收集一次CO2和总碳（CO2 +烃（CnHm））样品，以确定NPP附近多余的14C活性。提供每月积分样本的14C / 12C比的测量是在HEKAL的MICADAS型AMS上进行的。由于PWR型Paks反应堆的14CO2排放量相对较低以及局部的Suess效应，在研究的2年期间（2015-2016年），在纯CO2馏分中，被研究站的过量14C活性可忽略不计。相反，CnHm馏分中每个站都有可检测到的（尽管很小）过量。如果是二氧化碳，平均Δ14C过量为3。2015年2月，A3站的测量值为8‰，最高测量值为91.2‰。对于CnHm，2016年2月，A4站的平均超标值为31.1‰，最高测量值为319.1‰。我们采用了PC-CREAM 08建模以调查在环境采样站观测到的过量14 C活动，这取决于距NPP的距离和气象条件（例如风向和风速）。气象数据是在气象塔的Paks NPP作业区收集的。通过液体闪烁计数在NPP中测量了穿过120 m高烟囱的直接C-14排放。这些排放数据和我们的模型计算解释了A4站CnHm馏分中的过量活动，A4站沿盛行风向距NPP烟囱仅915 m。A3站（最远的单元）的过量活动可能来自附近的NPP废水排放点。最近观测到的平均过剩量和最高过剩数据与以前关于Paks NPP的研究（Molnár等人，2007; Veres等人，1995）中发表的数据相似，最高的14CO2和14CnHm的过量量仅比其高一点。在早期的研究中是这样，但是在这些以前的研究中，A3站没有配备放射性碳监测单元，并且从废水排放点几乎看不到放射性碳的排放水平。